The present invention relates to a closure device suitable for use in performing an assay, particularly a clinical test on a biological fluid such as blood. It is an object of the invention to provide a closure device which can render the reagent used in the assay into a state assuring a reliable test result and is able to maintain this state of the reagent over a long period of storage as well as under the stress of adverse environmental conditions, and furthermore to permit the addition of the reagent into the sample under assay at a desired time.
There is a need to provide a closure device permitting the assay to be carried out under maximally protected conditions thus eliminating the error factors imposed on the assay results by the environment and reducing the contamination risk imposed by the assay on the environment.
These goals and others can be attained by virtue of the closure device according to the invention, the device having its basic construction designed into a closure assembly suitable for closing the diagnostic test vessel, into which closure device the reagent after its preparation into an advantageous state for the assay is sealed in a manner permitting the release of the reagent from the closure device into the diagnostic test vessel at a desired instant of time.
Closure devices having a similar basic construction are known in the art, and their use has been contemplated in, e.g., the preparation of pharmaceuticals. In this application, the effective therapeutic drug is prepared from its basic constituents not earlier than at its required instant of use, whereby one or a number of the constituents of the pharmaceutical product are added to the other constituents stored in a medicine bottle or similar container just before the use of the drug. Prior to its addition, the first constituent(s) may have been stored in a closed space such as, e.g., the closure of the medicine bottle, wherefrom it can be taken into use by depressing or similarly actuating action on the closure, the action opening a passageway from the interior of the closure into the medicine bottle. Closure devices having this basic construction are described, i.a., in patent publications GB 1,193,989, GB 1,479,370, EP 0,093,090, EP 0,338,349, EP 0,561,322 and EP 0,344,849.
These conventional closures fail, however, to take into account the fact that a successful test in a great number of medical or similar applications requires the reagent used in the test to be in an advantageous state for the assay and that this state can be maintained up to the test instant, which instant may be essentially deferred from the ready-for-use manufacturing instant of closure device. Moreover, the circumstances prevailing during the standby period of the closure ready-for-use state may have been unfavorable to the stability of the reagent, particularly if the test kit is intended for field use.